Floor cleaning machine and method for operating a floor cleaning machine

ABSTRACT

A floor cleaning machine having a machine housing, cleaning-liquid and dirty-liquid tanks received in the machine housing, a chassis with front and rear wheels spaced apart along a longitudinal axis and facilitating movement of the machine housing over a floor surface, a cleaning device configured to clean the floor surface, a cleaning liquid applicator that dispenses a cleaning liquid from the cleaning-liquid tank to a region of the cleaning device, and a dirty-liquid intake that is in fluid communication with the dirty-liquid tank and configured to intake liquid on the floor surface and discharge the liquid to the dirty-liquid tank. The dirty-liquid intake being disposed on the machine housing behind the rear wheel and being movable relative to the machine housing between a retracted position and an extended position. The dirty liquid intake is closer to the rear wheel when disposed in the retracted position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority of German Patent Application No. 10 2022 111 608.5, filed May 10, 2022, the disclosure of which is incorporated by reference as if fully set forth in detail herein.

FIELD

The present disclosure relates to a floor cleaning machine and a related method for operating a floor cleaning machine.

BACKGROUND

Floor cleaning machines of this type are known from the prior art. During the operation of machines of this type, cleaning liquid, such as fresh water, is applied from the cleaning-liquid tank, by means of the device provided for this purpose, to the floor surface that is to be cleaned, wherein the cleaning elements engage with the floor surface in order to detach dirt therefrom in interaction with the cleaning liquid. Using the dirty-liquid intake device, which may for example be in the form of a suction foot, the cleaning liquid applied beforehand, which is charged with dirt after engagement of the cleaning elements with the floor surface such that it is a dirty liquid, is taken in again and brought into the dirty-liquid tank.

So-called scrubbing/suction machines of this type may be in the form of hand-guided or ride-on machines. In addition, it is possible for machines of this type to be in the form of autonomously driving so-called cleaning robots, such that no operator directly monitors the operation.

During the operation of machines of this type, however, the following problems can arise.

The dirty-liquid intake device, that is to say usually the suction foot, extends at least over the entire width of the floor cleaning machine and frequently also even projects laterally therefrom in order to ensure that cleaning liquid that has been applied to the floor surface that is to be cleaned is completely taken in again and brought into the dirty-liquid tank. A lateral projection beyond the width of the cleaning device is in particular therefore necessary in order that the dirty-liquid intake device covers the entire region in which dirty liquid has been distributed by the cleaning device, even when cornering.

In this respect, the dirty-liquid intake device, as seen in the direction of travel, is attached behind the rear wheels, which leads to the dirty-liquid intake device being pivoted outwards on that side of the machine that faces away from the inside of the corner whenever the machine performs cornering in one direction. This can lead to problems whenever the machine travels along an object, such as a shelf or a wall, and then is to be moved away therefrom laterally.

In this connection, it should be pointed out that, within the meaning of the present application, the term “object” is to be understood as having a meaning intended to cover any type of elements extending away from a floor surface that is to be cleaned. Accordingly, in addition to furnishing objects such as furniture, other objects that might be arranged only temporarily on the floor surface that is to be cleaned also fall under this meaning. Within the context of the present application, vertical walls are also intended to fall under this term.

In order to solve this problem, the prior art also discloses attaching the dirty-liquid intake device to the machine housing of the floor cleaning machine so as to be pivotable about a vertical axis, with the result that, whenever it comes into contact with another object during cornering, it can be pivoted away as a result.

However, it cannot be ruled out here that the contact between the lateral end of the dirty-liquid intake device and the object in question causes damage to the latter.

This problem of pivoting out is particularly relevant in the case of autonomously operated floor cleaning machines. Since they are not monitored by a user, during travel it is also not possible for the user to directly estimate whether the contact between the dirty-liquid intake device and the object with which its lateral end might come into contact will lead to damage or not.

Therefore, in the case of autonomously operated floor cleaning machines, it is absolutely necessary to avoid such contact between the dirty-liquid intake device and an object located laterally next to the floor cleaning machine. Therefore, in the case of autonomously operated floor cleaning machines, there is no consideration given to alleviating the problem of contact with laterally arranged objects by attaching the dirty-liquid intake device to the machine housing to as to be pivotable about a vertical axis, with the result that it can be pivoted out of the central position counter to a small resistance in the event of contact.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure provides a floor cleaning machine of which the dirty-liquid intake device is mounted in such a way that it can move along laterally close to objects and cornering away from the object is nevertheless possible, without contact occurring between the dirty-liquid intake device and the objects in question.

According to the disclosure, this can be achieved by a floor cleaning machine (1), having a machine housing which extends along a longitudinal axis of the floor cleaning machine between a front end and a rear end, having a cleaning-liquid tank which is received in the machine housing, having a dirty-liquid tank which is received in the machine housing, having a chassis which has wheels, bears the machine housing and is designed such that the floor cleaning machine can be moved over a floor surface that is to be cleaned, wherein the chassis comprises at least one front wheel and at least one rear wheel, which are spaced apart from one another along the longitudinal axis, wherein the chassis has a steerable design, with the result that a direction of travel, along which the floor cleaning machine moves over the floor surface that is to be cleaned, is variable, having a cleaning device with cleaning elements which are designed to engage with the floor surface that is to be cleaned when the floor cleaning machine is moved over the floor surface that is to be cleaned, having a device for applying cleaning liquid from the cleaning-liquid tank to the floor surface that is to be cleaned, said device being designed such that the cleaning liquid is applied in such a way that the cleaning liquid enters the region of the cleaning device, and having a dirty-liquid intake device, which extends perpendicularly in relation to the longitudinal axis and parallel to the floor surface that is to be cleaned, wherein the dirty-liquid intake device is designed to take in liquid located on the floor surface that is to be cleaned, with the result that said liquid can be delivered to the dirty-liquid tank, wherein the dirty-liquid intake device, as seen along the longitudinal axis, is arranged on the machine housing on that side of the rear wheel that faces away from the front wheel and wherein the dirty-liquid intake device is mounted on the machine housing so as to be displaceable between a retracted position and an extended position and wherein the dirty-liquid intake device, as seen along the longitudinal axis, is closer to the at least one rear wheel in the retracted position than in the extended position.

Accordingly, the floor cleaning machine according to the disclosure also comprises a chassis which has at least one front wheel and at least one rear wheel, bears a machine housing, and in which, inter alia, a cleaning-liquid tank and a dirty-liquid tank are received. The chassis can have two rear wheels that can be driven independently of one another and at least one adjustable front wheel. However, it is also conceivable for one or two actively steerable front wheels to be provided. In particular, the present disclosure is not limited to a specific design of the steerability.

In addition, a cleaning device with cleaning elements that can engage with the floor surface which is to be cleaned and over which the floor cleaning machine can be moved by means of the chassis, is mounted on the chassis. Furthermore, a cleaning device, having cleaning elements which can engage with the floor surface that is to be cleaned when the floor cleaning machine is moved over said floor surface using the chassis, is attached to the machine housing. By means of a corresponding device, which may for example be in the form of a nozzle arrangement, it is also possible to apply cleaning liquid from the cleaning-liquid tank to the floor surface that is to be cleaned such that said liquid enters the region of the cleaning device.

Lastly, a dirty-liquid intake device, which may for example be in the form of a suction foot, is arranged on the machine housing in such a way that, as seen along the longitudinal axis defined by the machine housing, said dirty-liquid intake device is located on that side of the rear wheel that faces away from the front wheel. The dirty-liquid intake device is thus attached in the region of the rear end and also behind the rear wheels, as seen in the direction of travel of the machine.

The dirty-liquid intake device is designed to take in dirty liquid located on the floor surface that is to be cleaned. For example, the dirty-liquid intake device can have a suction-extraction volume which is open over the entire width of the dirty-liquid intake device in relation to the floor surface that is to be cleaned and in addition is connected to the dirty-liquid tank. A pressure which is lower in comparison with the surroundings, that is to say a negative pressure, is generated in the dirty-liquid tank by a suction-extraction device, with the result that a stream of air is generated from the suction-extraction volume to the dirty-liquid tank that carries dirty liquid along and thus delivers it to the dirty-liquid tank.

According to the disclosure, it is now also provided that the dirty-liquid intake device is mounted on the machine housing so as to be displaceable between a retracted position and an extended position, wherein the dirty-liquid intake device is closer to the at least one rear wheel in the retracted position than in the extended position along the longitudinal axis that is defined by the machine housing and extends between the front and the rear end.

According to the disclosure, the dirty-liquid intake device can thus be displaced preferably parallel to the longitudinal axis. If the floor cleaning machine according to the disclosure is moved along an object, such as a shelf or a wall, at a small lateral distance and is to perform cornering away from this object, the dirty-liquid intake device is moved from the extended position to the retracted position, which leads to said dirty-liquid intake device pivoting out towards the object only to a small extent when the floor cleaning machine performs cornering away from the object.

If the floor cleaning machine, however, is not moved at a small lateral distance from an object and is to perform cornering, the dirty-liquid intake device remains in the extended position, in order to ensure that when the floor cleaning machine performs the cornering, the entire region that was passed over by the cleaning device beforehand and thus has dirty liquid is covered by the dirty-liquid intake device even on the outside of the corner.

The displaceability of the dirty-liquid intake device between two positions that are spaced apart as seen along the longitudinal axis thus makes it possible for the floor cleaning machine to be moved along an object at a small lateral distance and, proceeding from this, can perform cornering without the floor cleaning machine or its dirty-liquid intake device coming into contact with the object. The floor cleaning machine according to the disclosure can therefore move along closer to objects than is the case for machines according to the prior art, the safety-related requirements nevertheless being met.

In one example of the present disclosure, a drive device designed to drive at least one wheel of the chassis is provided. In this case, it is not necessary for a user to have to push or pull the machine, but rather the machine can move automatically.

Furthermore, it is preferred if a drive, such as a linear drive, designed to move the dirty-liquid intake device between the retracted position and the extended position is provided. Using this drive, the dirty-liquid intake device can then either be controlled by a user or displaced automatically from the extended position to the retracted position, and vice versa, in the event of cornering.

In a further example, a sensor arrangement configured to detect a distance, perpendicularly in relation to the longitudinal axis, between the machine housing and an object arranged to the side of the floor cleaning machine as seen along the longitudinal axis is provided. This makes it possible to automatically detect whether a lateral minimum distance from an object, at which the dirty-liquid intake device comes into contact with this object in the event of cornering, is exceeded. This can be indicated to a user in a further example. However, it is also possible for a corresponding signal to be correspondingly processed by a control unit of the floor cleaning machine.

In situations where a control unit signal-connected to the sensor arrangement and connected to the drive is provided, wherein the control unit is configured to control the drive such that the dirty-liquid intake device is moved into the retracted position when a distance detected by the sensor arrangement exceeds a predefined threshold value. In this embodiment, the dirty-liquid intake device is thus automatically displaced from the extended position to the retracted position when a certain minimum distance from a laterally arranged object is undershot.

In another example, the floor cleaning machine can be in the form of a so-called robot, wherein the control unit is configured to determine a route and control the floor cleaning machine such that it follows the route. Specifically, if the floor cleaning machine is in the form of a robot, the problem of contact between the dirty-liquid intake device and objects arranged to the side of the floor cleaning machine, as already explained, is particularly problematic because no user can directly estimate whether such contact will lead to damage. Therefore, in the case of such robots it is particularly advantageous when the dirty-liquid intake device is displaced between the extended position and the retracted position in automated fashion, as already described, using a drive and a sensor arrangement.

The dirty-liquid intake device can be mounted on the machine housing so as to be able to pivot about a vertical axis that runs relative to the machine housing such that, during operation, it extends perpendicularly in relation to the floor surface that is to be cleaned. This makes it possible for the dirty-liquid intake device to be displaced laterally when it comes into contact with an object.

In a further example, the dirty-liquid intake device is displaceable between a lowered and a raised position, wherein the dirty-liquid intake device is closer to a floor surface that is to be cleaned in the lowered position than in the raised position and wherein, in the lowered position, the dirty-liquid intake device can lie against the floor surface that is to be cleaned. It is thus possible for the dirty-liquid intake device to be displaced into an inoperative position, in which it is spaced apart from the floor surface that is to be cleaned and in which it is not damaged during travel over a floor surface.

The cleaning device can have a first width measured perpendicularly in relation to the longitudinal axis and for the dirty-liquid intake device to have a second width perpendicularly in relation to the longitudinal axis, wherein the second width is greater than or equal to the first width. As a result, as already explained, it is ensured that the dirty-liquid intake device covers the entire region, which was also in engagement with the cleaning device and on which dirty liquid is present, of the floor surface that is to be cleaned in the event of cornering.

The dirty-liquid intake device can be in the form of a so-called suction foot and has a main body, from which extend a front and a rear suction lip, which extend transversely in relation to the longitudinal axis and are spaced apart from one another in the direction of the longitudinal axis such that a suction-extraction volume is formed between the suction lips and the main body, wherein the suction lips are designed to come into abutment, by way of a bottom edge, with the floor surface that is to be cleaned and wherein a connecting line which extends between the main body and the dirty-liquid tank, such that the suction-extraction volume and the dirty-liquid tank are fluidically connected to one another, is provided. Further, a suction-extraction device can be connected to the dirty-liquid tank such that a negative pressure can be applied to the latter, which negative pressure in turn generates a stream of air is generated through the connecting line from the suction-extraction volume to the dirty-liquid tank that carries dirty liquid along from the suction-extraction volume to the dirty-liquid tank.

An operator control unit, which has operator control elements able to be actuated by a user, can be mounted on the machine housing, wherein the operator control unit, as seen along the longitudinal axis, can be displaced between a retracted position and an extended position, wherein the operator control unit, as seen along the longitudinal axis, is closer to the front end in the retracted position than in the extended position.

First of all, it is pointed out that the concept of an operator control unit that can be displaced, as seen along the longitudinal axis, between two positions spaced apart from one another is an independently inventive concept that can be used irrespective of the displaceability of the dirty-liquid intake device in the case of floor cleaning machines.

When the operator control unit can be displaced between a retracted position and an extended position, whether by hand or using a drive unit, specifically in the event of cornering the operator control unit can be prevented from coming into contact with objects in the region of the floor cleaning machine, this being achieved in that the operator control unit is displaced into the retracted position in such situations, if appropriate automatically by means of the drive unit. The extended position is advantageous, however, when the machine is guided by a user, since the operator control unit then also projects beyond the rear end of the machine housing and the user can be further away from the rear end, and thus the risk of them coming into contact with the dirty-liquid intake device and possibly damaging it is lower.

In a further aspect of the present disclosure, a method for operating a floor cleaning machine is provided wherein the method includes the following steps:

-   -   moving the floor cleaning machine over a floor surface that is         to be cleaned,     -   detecting a distance, perpendicularly in relation to the         longitudinal axis between the machine housing and an object         arranged to the side of the floor cleaning machine as seen along         the longitudinal axis, and,     -   if the distance detected by the sensor arrangement exceeds a         predefined threshold value, actuating a drive, with the result         that the dirty-liquid intake device is moved into the retracted         position.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 shows a side view of an exemplary embodiment of a floor cleaning machine according to the disclosure, with the operator control unit in the retracted position,

FIG. 2 shows a side view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the operator control unit in the extended position,

FIG. 3 shows an enlarged side view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the dirty-liquid intake device in the extended position and in the lowered position,

FIG. 4 shows an enlarged side view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the dirty-liquid intake device in the retracted position and in the lowered position,

FIG. 5 shows an enlarged side view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the dirty-liquid intake device in the retracted position and in the raised position,

FIG. 6 shows a perspective view, from below, of the dirty-liquid intake device of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 ,

FIG. 7 shows a plan view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the dirty-liquid intake device in the extended position, and

FIG. 8 shows a plan view of the exemplary embodiment of a floor cleaning machine according to the disclosure from FIG. 1 , with the dirty-liquid intake device in the retracted position.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

As can be seen in FIGS. 1 and 2 , the exemplary embodiment of a floor cleaning machine 1 according to the invention comprises a machine housing 3, in which a dirty-liquid tank 5 and a cleaning-liquid tank 7 are received. The floor cleaning machine 1 also comprises a chassis 9, which has two rear wheels 11 and a front wheel 13 that can be pivoted about a vertical axis, with the result that the floor cleaning machine 1 is designed to be moved by means of the chassis 9 over a floor surface 15 that is to be cleaned. The two rear wheels 11 are driven independently of one another, with the result that the floor cleaning machine 1 can be steered by selecting the speeds of the two rear wheels 11. As an alternative to a design with rear wheels 11 driven independently of one another, however, it is also conceivable for the front wheel 13 to have an actively steerable design. In any case, the present invention is not limited to a certain design for achieving the steerability.

The floor cleaning machine 1 is also provided with a drive device 17, which is coupled to the rear wheels 9 in such a way that they are driven in rotation by the drive device 17, with the result that the floor cleaning machine 1 can move automatically over a floor surface 15 that is to be cleaned. As already mentioned, the two rear wheels 11 can be driven at different speeds.

The floor cleaning machine 1 also comprises an operator control unit 19, which is arranged in the upper region of the machine housing 3 and has a multiplicity of operator control elements able to be actuated by a user. As is clear from a comparison of FIGS. 1 and 2 , the operator control unit 19 can be displaced between a retracted position, shown in FIG. 1 , and an extended position, illustrated in FIG. 2 . The machine housing 3 extends along a longitudinal axis 21 from a front end 23 to a rear end 25, and the operator control unit 19 is further away from the front end 23 in the extended position than in the retracted position. In particular, the operator control unit projects further beyond the rear end 25 of the machine housing 3 in the extended position (see FIG. 2 ) than is the case in the retracted position (FIG. 1 ). In one example, a drive unit designed to displace the operator control unit 19 between the retracted position and the extended position by means of a motor is provided. However, it is also conceivable for this displacement to be carried out manually by a user.

If the operator control unit 19 is in the extended position, a user walking along behind the machine 1 to operate it can reach the operator control elements provided therein better than is the case when the operator control unit 19 is in the retracted position. In particular, when the operator control unit 19 is in the extended position, the user can keep their distance from the rear end 25 of the floor cleaning machine 1 in order to operate it, so that a situation in which their feet enter the working region of the floor cleaning machine 1 is avoided.

The particular example of the floor cleaning machine 1 that is illustrated herein is in the form of an autonomous cleaning machine, i.e., a so-called floor cleaning robot, which is able to automatically determine a route and move over the floor surface 15 that is to be cleaned along said route. During autonomous operation, it is advantageous when the operator control unit 19 is in the retracted position, since it then does not project so far beyond the machine housing 3 and the risk of the operator control unit 19 coming into contact with objects in the surroundings of the floor cleaning machine 1 during steering maneuvers is minimized.

At this point, it should be noted that the present invention, however, it not limited to autonomous floor cleaning machines and/or those in the case of which the user must walk along behind the machine. Rather, the present invention also extends to floor cleaning machines in the case of which the user can sit on the machine during operation, that is to say so-called ride-on machines.

As can also be seen in FIGS. 1 and 2 , the floor cleaning machine 1 comprises a cleaning device 27 with cleaning elements 29 in the form of bristles of a roller brush, not illustrated in detail, wherein the roller brush is driven in rotation so that the bristles 29 can come into engagement with the floor surface 15 that is to be cleaned, when the floor cleaning machine 1 is moved over the floor surface 15. Moreover, provided in the region of the cleaning device 27 is a device 31, which may be in the form of nozzles, which is connected to the cleaning-liquid tank 7 and designed to apply cleaning liquid to the floor surface 15 that is to be cleaned in the region of the cleaning device 27.

In addition, provided in the region of the front wheel 13 are lateral brushes 33, which likewise can engage with the floor surface 15 that is to be cleaned and are driven in rotation in order to deliver dirt located in the side region of the path of travel of the floor cleaning machine 1 towards the middle.

Since the exemplary embodiment described here of a floor cleaning machine 1 according to the present disclosure is in the form of a robot, it has a sensor arrangement of multiple distance sensors 35, which are connected to a control unit 39 of the floor cleaning machine 1 via signal lines 37, wherein the control unit 39 in turn is connected to the drive device 17 of the floor cleaning machine 1 such that the control unit 39 can actuate the drive device 17. Furthermore, the control unit 39 is also connected to a servomotor (not illustrated), via which the steering angle of the front wheel 13 can be set. As a result, the control unit 39 is designed to autonomously control the movement of the floor cleaning machine 1 over the floor surface 15 that is to be cleaned. Using the sensors 35 attached to the machine housing 3, in this respect it is possible to detect, inter alia, whether there are objects, such as furniture or walls, to the side of the floor cleaning machine 1 and how great the distance from them is.

Lastly, a dirty-liquid intake device 41, which is illustrated in detail in FIGS. 3 to 6 and in the present exemplary embodiment is in the form of a suction foot arrangement, is provided in the region of the rear end 25 of the machine housing 3 of the floor cleaning machine 1.

As these figures in particular show, the dirty-liquid intake device 41 has a main body 43 from which a front suction lip 45 and a rear suction lip 47 extend downwards, wherein the suction lips 45, 47 extend transversely in relation to the longitudinal axis 21 and are spaced apart from one another in the direction of the longitudinal axis 21. The main body 43 and the suction lips 45, 47 delimit a suction-extraction volume 49, which is open towards the floor surface 15 that is to be cleaned, but closed off when the bottom edges of the suction lips 45, 47 come into contact with the floor surface 15 that is to be cleaned.

A port, which is not illustrated, is provided on the main body 43, with the result that the dirty-liquid tank 5 is connected to the suction-extraction volume 49 by way of a connecting line (not illustrated). The dirty-liquid tank 5 is in turn connected to a suction-extraction device 51, with the result that a pressure which is lower than the ambient pressure can be generated in the interior of the dirty-liquid tank 5, with the result that in turn a stream of air can be generated from the suction-extraction volume 49 to the dirty-liquid tank 5 that then carries along the dirty liquid located on the floor surface 15 that is to be cleaned and delivers it to the dirty-liquid tank 5.

The dirty-liquid intake device 41 is mounted via its main body 43 on a guide rod 53, which in turn is attached to a mount 57 so as to be pivotable about a pivot axis 55. The mount 57 in turn can be displaced by means of a motor along a guide rail 61 using a linear drive 59, in a direction substantially parallel to the floor surface 15 that is to be cleaned and also parallel to the longitudinal axis 21 with respect to the machine housing 3, wherein the linear drive 59 is connected to the control unit 39 in a manner not illustrated. Using the linear drive 59, the dirty-liquid intake device 41 can thus be displaced parallel to the longitudinal axis 21 between a retracted position (FIGS. 4 and 5 ) and an extended position (FIG. 3 ).

Using the linear drive 59, the dirty-liquid intake device 41 in the form of a suction foot can be brought into the extended position illustrated in FIG. 3 , in which the dirty-liquid intake device 41 projects further beyond the rear end 25 of the machine housing 3, i.e. the dirty-liquid intake device 41, as seen along the longitudinal axis 21, is further away from the rear wheel 11 than it is in the retracted position shown in FIGS. 4 and 5 , which is achieved in that the linear drive 59 is retracted, so that the mount 57 on which the guide rod 53 is mounted is moved along the guide rail 61 towards the rear wheel 11.

This is effected first of all up to the point at which an oblique stop surface 65 provided at that end 63 of the guide rod 53 that is remote from the dirty-liquid intake device 41 comes into contact with a supporting element in the form of a bearing 67 (see FIG. 4 ). When the linear drive 59 is then retracted further, the stop surface 65 moves along the bearing 67, with the result that the guide rod 53 is pivoted about the pivot axis 55 and that end of the guide rod 53 that bears the dirty-liquid intake device 41 moves from a lowered position (FIG. 4 ) to a raised position (FIG. 5 ), in which the dirty-liquid intake device 41 is further away from the floor surface 15 that is to be cleaned than in the lowered position.

Lastly, it can be seen in FIGS. 3 to 5 that the dirty-liquid intake device 41 in the form of a suction foot can be pivoted about a vertical axis 69, which, during operation, that is to say when the dirty-liquid intake device 41 is in the lowered position, runs substantially perpendicularly in relation to the floor surface 15 that is to be cleaned. Such a position, pivoted out of a straight position of the suction foot, can be seen in FIG. 7 , this being the result of the free ends 71 of the dirty-liquid intake device 41 having different positions as seen along the longitudinal axis 21.

Moreover, it can likewise be seen in FIGS. 7 and 8 that the width of the dirty-liquid intake device 41 is clearly greater than the width of the cleaning device 27, wherein these widths are each determined perpendicularly in relation to the longitudinal axis 21.

The displacement of the dirty-liquid intake device 41 between the extended position (FIGS. 3 and 7 ) and the retracted position (FIGS. 4 and 8 ) achieves the following.

When the dirty-liquid intake device 41 is in the extended position and cornering of the floor cleaning machine 1 along the arrow 73 in FIG. 7 is to be performed, the free end 71, which is on the right in FIG. 7 , of the dirty-liquid intake device 41 moves along the circular path 75, so that objects located in the region of this circular path might collide with the free end 71. When, however, the dirty-liquid intake device 41 is displaced into the retracted position using the linear drive 59, as shown in FIG. 8 , the diameter of the circular path decreases considerably, with the result that cornering, as indicated by the arrow 73 in FIGS. 7 and 8 , can still be performed even if objects are arranged laterally relatively close to the floor cleaning machine 1.

Consequently, during autonomous operation of the floor cleaning machine 1 using the sensors 35 and the control unit 39 the following method steps can be carried out:

-   -   using the drive device 17, moving the floor cleaning machine 1         over the floor surface 15 that is to be cleaned,     -   detecting a distance, perpendicularly in relation to the         longitudinal axis 21, between the machine housing 3 and an         object arranged to the side of the floor cleaning machine 1 as         seen along the longitudinal axis 21, and,     -   if the distance detected by the sensors 35 of the sensor         arrangement exceeds a predefined threshold value, actuating a         linear drive 59, with the result that the dirty-liquid intake         device 41 is moved into the retracted position.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

List of Reference Signs 1 Floor cleaning machine 3 Machine housing 5 Dirty-liquid tank 7 Cleaning-liquid tank 9 Chassis 11 Rear wheel 13 Front wheel 15 Floor surface to be cleaned 17 Drive 19 Operator control unit 21 Longitudinal axis 23 Front end 25 Rear end 27 Cleaning device 29 Cleaning elements 31 Device for dispensing cleaning liquid 33 Side brush 35 Sensors 37 Signal line 39 Control unit 41 Dirty-liquid intake device 43 Main body 45 Front suction lip 47 Rear suction lip 49 Suction-extraction volume 51 Suction-extraction device 53 Guiding rod 55 Pivot axis 57 Mount 59 Linear drive 61 Guide rail 63 End of guiding rod 65 Stop surface 67 Bearing 69 Vertical axis 71 Free end 73 Cornering direction 75 Circular path 

What is claimed is:
 1. A floor cleaning machine (1), having a machine housing (3) which extends along a longitudinal axis (21) between a front end (23) and a rear end (25), having a cleaning-liquid tank (7) which is received in the machine housing (3), having a dirty-liquid tank (5) which is received in the machine housing (3), having a chassis (9) which has wheels (11, 13), bears the machine housing (3) and is designed such that the floor cleaning machine (1) can be moved over a floor surface (15) that is to be cleaned, wherein the chassis (9) comprises at least one front wheel (13) and at least one rear wheel (11), which are spaced apart from one another along the longitudinal axis (21), wherein the chassis (9) has a steerable design, with the result that a direction of travel (73), along which the floor cleaning machine (1) moves over the floor surface (15) that is to be cleaned, is variable, having a cleaning device (27) with cleaning elements (29) which are designed to engage with the floor surface (15) that is to be cleaned when the floor cleaning machine (1) is moved over the floor surface (15) that is to be cleaned, having a device (31) for applying cleaning liquid from the cleaning-liquid tank (7) to the floor surface (15) that is to be cleaned, said device being designed such that the cleaning liquid is applied in such a way that the cleaning liquid enters the region of the cleaning device (27), and having a dirty-liquid intake device (41), which extends perpendicularly in relation to the longitudinal axis (21) and parallel to the floor surface (15) that is to be cleaned, wherein the dirty-liquid intake device (41) is designed to take in liquid located on the floor surface (15) that is to be cleaned, with the result that said liquid can be delivered to the dirty-liquid tank (5), wherein the dirty-liquid intake device (41), as seen along the longitudinal axis (21), is arranged on the machine housing (3) on that side of the rear wheel (11) that faces away from the front wheel (13) and wherein the dirty-liquid intake device (41) is mounted on the machine housing (3) so as to be displaceable between a retracted position and an extended position and wherein the dirty-liquid intake device (41), as seen along the longitudinal axis (21), is closer to the at least one rear wheel (11) in the retracted position than in the extended position.
 2. The floor cleaning machine (1) according to claim 1, wherein a drive device (17) designed to drive at least one wheel (11, 13) of the chassis (9) is provided.
 3. The floor cleaning machine (1) according to claim 1, wherein a drive, preferably a linear drive (59), designed to move the dirty-liquid intake device (41) between the retracted position and the extended position is provided.
 4. The floor cleaning machine (1) according to claim 3, wherein a sensor arrangement (35) designed to detect a distance, perpendicularly in relation to the longitudinal axis (21), between the machine housing (3) and an object arranged to the side of the floor cleaning machine (1) as seen along the longitudinal axis (21) is provided.
 5. The floor cleaning machine (1) according to claim 4, wherein a control unit (39) signal-connected to the sensor arrangement (35) and connected to the drive (59) is provided, wherein the control unit (39) is configured to control the drive (59) such that the dirty-liquid intake device (41) is moved into the retracted position when a distance detected by the sensor arrangement (35) exceeds a predefined threshold value.
 6. The floor cleaning machine (1) according to claim 5, wherein the control unit (39) is configured to determine a route and control the floor cleaning machine (1) such that it follows the route.
 7. The floor cleaning machine (1) according to claim 1, wherein the dirty-liquid intake device (41) can be displaced parallel to the longitudinal axis (21) relative to the machine housing (3).
 8. The floor cleaning machine (1) according to claim 1, wherein the dirty-liquid intake device (41) is mounted on the machine housing so as to be able to pivot about a vertical axis that runs relative to the machine housing such that, during operation, it extends perpendicularly in relation to the floor surface that is to be cleaned.
 9. The floor cleaning machine (1) according to claim 1, wherein the dirty-liquid intake device (41) can be displaced between a lowered and a raised position, wherein the dirty-liquid intake device (41) is closer to a floor surface (15) that is to be cleaned in the lowered position than in the raised position and wherein, in the lowered position, the dirty-liquid intake device (41) preferably lies against the floor surface (15) that is to be cleaned.
 10. The floor cleaning machine (1) according to claim 1, wherein the cleaning device (27) has a first width measured perpendicularly in relation to the longitudinal axis (21) and wherein the dirty-liquid intake device (41) has a second width measured perpendicularly in relation to the longitudinal axis (21) and wherein the second width is greater than or equal to the first width.
 11. The floor cleaning machine (1) according claim 1, wherein the dirty-liquid intake device (41) has a main body (43), from which extend a front and a rear suction lip (45, 47), which extend transversely in relation to the longitudinal axis (21) and are spaced apart from one another in the direction of the longitudinal axis (21) such that a suction-extraction volume (49) is formed between the suction lips (45, 47) and the main body (43), wherein the suction lips (45, 47) are designed to come into abutment, by way of a bottom edge, with the floor surface (15) that is to be cleaned and wherein a connecting line which extends between the main body (43) and the dirty-liquid tank (5), such that the suction-extraction volume (49) and the dirty-liquid tank (5) are fluidically connected to one another, is provided.
 12. The floor cleaning machine (1) according to claim 1, wherein an operator control unit (19), which has operator control elements able to be actuated by a user, is mounted on the machine housing (3), wherein the operator control unit (19), as seen along the longitudinal axis (21), can be displaced between a retracted position and an extended position, wherein the operator control unit (19), as seen along the longitudinal axis (21), is closer to the front end (23) in the retracted position than in the extended position.
 13. A method for operating a floor cleaning machine (1) over a floor surface (15) that is to be cleaned, the floor cleaning machine (1) having a machine housing (3), a cleaning-liquid tank (7), a dirty-liquid tank (5), a chassis (9), a cleaning device (27), a cleaning liquid applicator (31) and a dirty-liquid intake (41), the machine housing (3) extending along a longitudinal axis (21) between a front end (23) and a rear end (25), the cleaning-liquid tank (7) being received in the machine housing (3), the dirty-liquid tank (5) being received in the machine housing (3), the chassis (9) having a plurality of wheels (11, 13), the wheels (11, 13) comprising at least one front wheel (13) and at least one rear wheel (11) that are spaced apart from one another along the longitudinal axis (21), the chassis (9) bearing the machine housing (3) and being configured to facilitate movement of the floor cleaning machine (1) over the floor surface (15) along a direction of travel (73), wherein the chassis (9) is steerable to vary the direction of travel (73), the cleaning device (27) having cleaning elements (29) that are configured to engage with the floor surface (15) when the floor cleaning machine (1) is moved over the floor surface (15), the cleaning liquid applicator (31) in fluid communication with the cleaning-liquid tank (7) and being configured to dispense cleaning liquid received from the cleaning liquid tank (7) into a region of the cleaning device (27), the dirty-liquid intake (41) extending perpendicularly in relation to the longitudinal axis (21) and parallel to the floor surface (15), the dirty-liquid intake (41) being in fluid communication with the dirty-liquid tank (5) and configured to intake a liquid on the floor surface (15) and discharge the liquid to the dirty-liquid tank (5), wherein the dirty-liquid intake (41), as seen along the longitudinal axis (21), is arranged on the machine housing (3) on that side of the rear wheel (11) that faces away from the front wheel (13), wherein the dirty-liquid intake (41) is mounted on the machine housing (3) so as to be displaceable between a retracted position and an extended position and wherein the dirty-liquid intake (41), as seen along the longitudinal axis (21), is closer to the at least one rear wheel (11) in the retracted position than in the extended position, the said method comprising: moving the floor cleaning machine (1) over the floor surface (15), detecting a distance, perpendicularly in relation to the longitudinal axis (21), between the machine housing (3) and an object arranged to the side of the floor cleaning machine (1) as seen along the longitudinal axis, and, if the distance detected by the sensor arrangement (35) exceeds a predefined threshold value, actuating a drive (59) to move the dirty-liquid intake (41) into the retracted position. 